1. Field of the Invention
The present invention relates to an image projector and an image display that includes the image projector and a directional reflection screen.
2. Description of the Related Art
Conventionally, as the image display formed by combining the directional reflection screen with the image projector, there have been known apparatuses such as a 3-dimensional display using the principle of binocular parallax. The fundamental principle of the directional reflection screen that uses a corner reflective-mirror group as a light-converging method in the horizontal direction has been disclosed on, for example, page 28 and pp. 91-97 in Takayoshi Oukoshi, xe2x80x9cThree Dimensional Image Engineeringxe2x80x9d, Asakura Bookstore Press.
FIG. 6 illustrates a directional reflection screen disclosed in JP-A-10-186522, which has been manufactured using the technology based on the above-described principle. Combining a 2-plane orthogonal corner reflective-mirror group 31 with a lenticular board 32 configures a screen 3. Incident light into the screen is converged and reflected in the horizontal direction by the 2-plane orthogonal corner reflective-mirror group 31, and the incident light is diffused and reflected in the vertical direction by the lenticular board 32.
FIG. 9 illustrates the state where, when an image is projected onto the above-described screen 3, the reflection of the light is seen from the above. Since the light reflected by the screen 3 is converged onto the positions of two image projectors 51, 52 in the horizontal direction, the two image projectors 51, 52 are located directly above or below a right eye and a left eye of a viewer 20, respectively. At the same time, a pair of image signals becoming a 3-dimensional image signal based on the principle of the binocular parallax is projected and irradiated onto the screen 3. This operation allows the viewer 20 to view the 3-dimensional image.
Here, although the above-described explanation is about the 3-dimensional image, a 2-dimensional image can be viewed when projecting identical image signals from the two image projectors 51, 52. Also, it is needless to say that, when using only one image projector, the 2-dimensional image can also be viewed.
As is obvious from the above-described prior art, a width in the horizontal direction of the light emitted from a projection lens in the image projector toward the screen is equal to a width in the horizontal direction where the viewer is able to view the image. Accordingly, if the image projector is downsized for implementing, for example, space-saving, the projection lens is also reduced in association therewith, thus narrowing the viewing area. In order not to narrow the viewing area, it is considered That the other optical systems in the image projector are downsized with only a size of the projection lens kept unchanged. In this consideration, however, the light is emitted from only a portion of range of the projection lens, resulting in no improvement in the viewing area.
It is an object of the present invention to provide an image projector and an image display where the viewing area in the horizontal direction is extended.
In order to solve the above-described problem, it is preferable and appropriate to extend lights in an entrance pupil of the projection lens in the image projector so that the lights are overlapped with each other at least in the horizontal direction, the lights having passed through or reflected from the respective positions on the LCD panel.
Here, the phrase xe2x80x9cthe respective positions on the LCD panelxe2x80x9d means the respective pixels of the LCD panel. The phrase xe2x80x9chaving passed through or reflected fromxe2x80x9d means that the LCD panel is of xe2x80x9ca transmittance type or a reflection typexe2x80x9d. The phrase xe2x80x9care overlapped with each other in the horizontal directionxe2x80x9d means that, when the extended states of the lights into the horizontal direction are compared with each other in the entrance pupil of the projection lens, the lights attaining from the respective pixels exist in a certain range in the horizontal direction, the lights having passed through or reflected from the respective positions on the LCD panel. The phrase xe2x80x9care overlapped with each other at least in the horizontal directionxe2x80x9d means that the lights existing in this range include states of being located apart from each other in the vertical direction. The lights, of course, include states of being overlapped with each other not only in the horizontal direction but also in the vertical direction. The phrases xe2x80x9cthe horizontal direction and the vertical directionxe2x80x9d correspond to xe2x80x9cthe horizontal direction and the vertical directionxe2x80x9d used usually in the directional reflection screen illustrated in FIG. 6. In the directional reflection screen, a direction obtained by connecting the both eyes of the viewer is xe2x80x9cthe horizontal directionxe2x80x9d.
When the lights in these states are emitted from 15 the image projector and enter the directional reflection screen, even in the case of the lights existing in the states of being located apart from each other in the vertical direction, the lights that have been reflected by the directional reflection screen and have returned back to an exit pupil of the projection lens are overlapped with each other in the vertical direction. This is attributed to the fact that the directional reflection screen has the function of diffusing and reflecting the incident light in the vertical direction. Also, the lights that have returned back to the exit pupil, in the horizontal direction, are overlapped with each other in a range that is equal to the range at the time of the emission from the exit pupil. Consequently, the exit pupil is located directly above or below the viewer, thereby allowing the viewer to view an image without being chipped.
As having been described so far, in summary, the image projector in the present invention is characterized by including a light source, the LCD panel that the lights emitted from the light source enter, and the projection lens that the lights emitted from the LCD panel enter, wherein there exists, in the entrance pupil of the projection lens, a range in which the lights emitted from the respective pixels of the LCD panel are overlapped with each other at least in the horizontal direction. The LCD panel may be of either the transmittance type or the reflection type.
Also, the image display in the present invention is characterized by being formed by locating the image projector and the directional reflection screen in such a manner as to be in parallel to the horizontal direction.
The present invention permits a conventionally chipped image to be viewed in a state of being not chipped. In addition to this, the present invention makes it possible to extend further the viewing area in the state.